Synthetic methods and apparatuses using plasma torches using electromagnetic waves and a high frequency have been developed and introduced.
Prior-art Patent Document 1 (Korean Registered Patent No. 10-0631828) discloses an integral inductively coupled plasma torch having a cylindrical induction coil structure.
Prior-art Patent Document 1 discloses a configuration in which double ring-shaped channels (23 and 24) are obtained between a torch outer wall and an induction coil structure and between the induction coil structure and a plasma confinement tube by forming an induction coil portion of the high-frequency plasma torch to have a cylindrical induction coil structure and coaxially disposing the cylindrical induction coil structure between the outer wall and the plasma confinement tube, and main components of the torch are isolated into the torch outer wall, the induction coil structure, and the plasma confinement tube by integrating the induction coil structure and the torch outer wall through a high-frequency input terminal to optionally select and use optimum materials and processing methods for the respective components of the torch, thereby improving the performance and economic feasibility of the torch.
According to such a conventional high-frequency plasma torch, the high-frequency plasma torch may be used to melt or evaporate a solid powder or a spray liquid injection by heating the solid powder or the spray liquid injection using high-temperature (8,000 to 10,000 K) thermal plasma formed in a wide and large volume in the torch, or used to increase thermal cracking or enthalpy by heating a gas. Since such tasks are generally performed in a confinement tube made of a refractory material capable of withstanding a temperature of 2,000 K or more, or performed outside of an outlet of the confinement tube to ignite plasma sparks in the form of a jet, the high-frequency plasma torch has been used in various fields such as spray coating of high melting point materials, ultrafine powder synthesis, chemical vapor deposition, waste incineration, and thermal cracking, and its applicability has increased in various fields for the development of new technology.
High-frequency plasma torches having characteristics, such as electrodeless discharging, a large volume, a suitable gas velocity, and the like, seem to be desirably applied to various scientific and industrial fields. However, the absence of electrodes forces the high-frequency plasma torch to be very sensitive to external disturbance factors such as an inflow of a reactant into plasma. In effect, when an amount of the reactant is greater than a predetermined small amount, the inflow of the reactant into the plasma causes fluctuations of the plasma to induce quick quenching of the plasma. The sensitive characteristics of such high-frequency plasma serve as the disturbance factor in expansion to various fields.
Therefore, it is no exaggeration to say that success or failure of an operation of the high-frequency plasma torch in various fields especially depends on whether plasma is stably maintained when the reactant is injected into plasma. For this purpose, when a high-temperature (approximately 5,000 K) and high-density plasma flow is introduced into a high-frequency plasma generation region, quick quenching of high-frequency plasma may be realized, and instability resulting from the quick quenching may be overcome.
Accordingly, the present inventors have conducted research in recognition of such problems, and developed an electromagnetic wave/high frequency hybrid plasma torch capable of realizing quick quenching of high-frequency plasma and overcoming instability resulting from the quick quenching by introducing the following configurations to solve the problems of the conventional high-frequency plasma torch.